Post-wash fabric treating method

ABSTRACT

A fabric treating composition for use in preventing the staining of fabrics consisting essentially of an aqueous solution of a complexing acid and a cationic fabric softening agent, the complexing acid and the softening agent being present in amounts so that on dilution with water the complexing acid comprises from 0.01 to 0.1% by weight of the dilution and the softening agent comprises from 0 to 0.1% of the dilution.

United States Patent [191 Ramachandran Sept. 9, 1975 POST-WASH FABRICTREATING METHOD [75] Inventor: Pallassana Ramachandran,

Robinsville, NJ

[73] Assignee: Colgate-Palmolive Company, New

York, NY.

22 Filed: Sept. 7, 1972 211 Appl. No.: 286,995

[52] US. Cl. 8/137; 8/139; 252/8.6; 252/8.8

[51] Int. Cl. BOSB 3/00 [58] Field of Search 252/8.6, 8.8, 142; 8/137,8/139 [56] References Cited UNITED STATES PATENTS 3,637,495 1/1972Eckert et a1. 252/8.6 X

2/1972 Heins et a1 252/8.6 X 7/1972 Ciko 252/142 Primary ExaminerStephenJ. Lechert, Jr. Attorney, Agent, or Firm-S. J. Baron; H. S. Sylvester;N. M. Blumenkoph [57 ABSTRACT 9 Claims, No Drawings POST-WASH FABRICTREATING METHOD This invention relates to a post-washin g treatingcomposition and method for using the same. More particularly, thisinvention relates to a post-washing treating composition and methodwhich effectively prevents staining or yellowing of fabrics by metalions.

Although cationic fabric treating fabric softening agents have beenknown and utilizedsince the early l930s, the use of the cationic fabrictreating agents has decreased as compared to the nonionic fabricsoftening agents since the cationic fabric softening agents have amarked tendency to impart a yellowness to fabrics which are continuallytreated with the same. Furthermore, the cationic fabric softening agentscan only be utilized in the rinse cycle since the majority ofcommercially available detergents are of the anionic type and are notcompatible with these cationic fabric softening agents. The cationicfabric softening agents, although less preferred, are generally lessexpensive to utilize and, accordingly, it would be desirable to be ableto utilize such cationic agents in the rinse cycle without causing thefabrics be become yellowed.

In addition to yellowness imparted by cationic fabric softening agents,the fabrics are often stained by metal cations present in various soils,especially clay type soils. Up to now the only means for treating thesemetal type stains was the removal of the stains subsequent to theirsetting on the fabrics by way of bleaching and repeated washing. Each ofthese treatments, of course, is not completely satisfactory sincecontinued bleaching of fabrics tends to degrade the same and shortenstheir useful life. The continued washing is not completely effective inremoving the stains and tends to impart a certain boardiness to thefabrics, thus necessitating the use of a fabric softener.

Although complexing acids, such as citric acid, and the salts of theseacids have been recently employed as supplemental builders for use inconjunction with various detergent compositions as replacements for thephosphate and nitrilo type builders previously employed, these materialshave not been utilized in postwashing fabric treating compositions, suchas fabric softeners. Citric acid and other complexing acids have foundutility for a wide number of uses ranging from a use as a wall paperpaste remover to use as an active ingredient in a detergent compositionfor removing fishy type odors.

It is, therefore, within the above environment and disadvantages thatthe composition and process of the present invention has been developed.Briefly, the fabric treating composition of the present invention whichis for use in preventing the staining of fabrics consists essentially ofan aqueous solution of a complexing acid selected from the groupconsisting of citric acid, maleic acid, tartaric acid, fumaric acid,adipic acid, succinic acid and mixtures thereof and a cationic fabricsoftening agent such that on dilution with water the resultingcomposition contains from 0.01 to 0.1% by weight of complexing agent andfrom O to 0.1% by weight of softening agent. The method of the presentinvention comprises a method for preventing the yellowing or staining offabrics comprising treating a fabric in the rinse with an aqueoussolution consisting essentially of water, a complexing acid selectedfrom the group consisting of citric acid, maleic acid, tartaric acid,fumaric acid, adipic acid, succinic acid and mixtures thereof and acationic fabriclsoftener, the complexing acid and cationic fabricsoftener being present in amounts sufficient to produce a concentrationof from about 0.01 to 0.10% by weight of the acid and from about 0 to0.10% by weight of the cationic fabric softener.

It is, therefore, the primary object of the present invention to providea fabric treating composition which effectively prevents yellowing andstaining of fabrics.

It is a further object of the present invention to provide a method forpreventing the staining and yellowing of fabrics by rinsing the fabricsin a solution consisting essentially of water, a complexing acid and acationic fabric softener.

It is a still further object of the present invention to provide amethod wherein the fabrics are treated so as to prevent the same frombeing stained by the subsequent soiling with mineral containing soils.

It is a still further object of the present invention to provide amethod for preventing fabrics from yellowing through the continued useof a cationic fabric softening agent.

Still further objects and advantages of the composition and process ofthe present invention will become more apparent from the following, moredetailed description thereof. I

The composition of the present invention which obviates the abovedisadvantages and which is for use in preventing the staining oryellowing of fabrics consists essentially of anaqueous solution of acomplexing acid selected from a group consisting of citric acid, maleicacid, tartaric acid, fumaric acid, adipic acid, succinic acid andmixtures thereof, and a cationic fabric softening agent in an amountsufficient to produce, upon dilution, a concentration of from 0.01 to0.1% by weight of complexing acid and 0 to 0.1% by weight softeningagent.

The process of the present invention comprises rinsing a fabric in anaqueous solution consisting essentially of water, a complexing acid andacationic fabric softening agent wherein the cationic fabric softeningagent and the complexing acid are present in amounts sufficient toproduce a concentration of from 0.01% to 0.10% by weight of thecomplexing acid and from 0 to 0.10% by weight of the cationic fabricsoftening agent.

The primary ingredient in the composition of the present invention isthe complexing acid which is selected from citric acid, maleic acid,tartaric acid, fumaric acid, adipic acid, succinic acid and mixturesthereof. The preferred acids are citric and tartaric acid with citricbeing most preferred.

The complexing acid may be present in the final diluted rinse solutionin an amount ranging from 0.01 to 0.1% by weight and preferably 0.02 to0.05% by weight. Of course, it will be most convenient to utilize aconcentrated solution of the acid for consumer convenience and packagingeconomies. Generally, since most top loading washing machines have from15 to 20 gallon capacity, the concentrated form of the composition willgenerally comprise from 2 to 25% by weight of acid in a water solution.The important parameter is the dilution concentration so any concentratecomposition will be solely for convenience in use.

In use, a small amount of the complexing acid is deposited on the fabricso as to provide active complexing sites for metal ions contained insoils, etc. In essence, the present composition and process are of apreventative nature since, by depositing a small amount of acid on thefabric, future metal stains are virtually eliminated. The samecomplexing acid also prevents the yellowing of fabrics due to a build-upof cationic fabric softeners.

Fabric softeners must be strongly attracted to fabrics in order tofunction properly; however, this attraction which is especially strongin cationic softeners also causes softener buildup or yellowing. Thecomplexing acids, when used in conjunction with cationic fabricsofteners lessen the tendency to build-up without interfering with theirsoftening function.

Although in conventional compositions and processes, the salts of theseorganic, complexing acids are often utilized with similar or equivalentresults, the sodium salts of the above noted acids as well as the otheralkaline and the alkaline earth salts do not have the complexingproperties necessary for the enhancement of the removal of the soil fromthe fabric. Accordingly, in the process and composition of the presentinvention, only the acids themselves and not their salts may beutilized.

Furthermore, only the organic complexing acids aid in the removal ofthese ions since the removal is not a function of pH as demonstrated bythe inability of mineral acid solutions to effectively prevent stainingfrom irremovable metal ions. Also, these latter acids are too strong forcontinued use since they tend to degrade the fibers.

The cationic fabric softening compounds useful in the composition of thepresent invention generally comprise cationic nitrogen containingcompounds, such as quarternary ammonium compounds and amines containingone or two straight chained organic radicals of at least 8 carbon atomsand preferably containing at least one straight chained organic radicalcontaining from 12 to 22 carbon atoms.

Generally, the quarternary ammonium softening agents have the followingformulas (CH CH O) H as a halide, i.e., chloride, bromide, iodide; asulfate, acetate, hydroxide, methasulfate or similar inorganic ororganic solubilizing monoor dibasic radical. Examples of quaternaryammonium softening agents suitable for use in the composition of thepresent invention include the following: hydrogenated ditallow dimethylammonium chloride, ethoxylated distearyl dimethyl ammonium chloride,l-hydroxyethyll -methyl-2-heptadecyl imidazolinium chloride; dimethyldistearyl ammonium chloride; trimethyl stearyl ammonium bromide; cetyltrimethyl ammonium chloride, di-coco dimethyl ammonium chloride; cetylpyridinium chloride; higher alkyl dimethyl benzyl ammonium chloride;di-isobutyl phenoxy ethoxy ethyl dimethyl benzyl ammonium chloride;lauryl isoquinolinium bromide; distearyl dimethyl quarternary ammoniumbromide; distearyl dimethyl quaternary ammonium methylsulfate; dicocodimethyl quaternary ammonium chloride; dimethyl arachidyl, behenylquaternary ammonium chloride; di-(soya) dimethylammonium chloride, anddi-(coco) dimethylammonium chloride.

Examples of amines which may be utilized in the composition of thepresent invention include primary tallow amine, primary coco amine,primary halogenated tallow amine, n-tallow 1,3-propylene diamine, oleyl1,3-propylene diamine, and coco 1,3-propylene diamine.

The term coco when utilized refers to fatty acid groups formed incoconut oil fatty acids. Such acids contain from about 8 to 18 carbonatoms per molecule predominating in the C acids.

Although the process and composition of the present invention areoperative without the use of the cationic softeners, it is a preferredembodiment to utilize a mixture of the complexing acid and softener in asolution. Generally, the softener comprises from 0 to 0.1% by weight ofthe rinse water subsequent to dilution and preferably from 0.01 to 0.03%by weight. As with the acid, the softener will have a similarconcentration in the concentrate, i.e., from 0 to 25% by weight.

Another important factor in the composition of the present invention isthe ratio by weight of the cationic agent to the anti-yellowing agent,i.e., the complexing acid, since within certain ratios the non-yellowingproperties are most evident. This ratio is generally from 1: l toapproximately 1:5 softener to acid with optimum results being obtainedat a ratio of approximately 1:2.

Furthermore, it has been found that the process of the present inventionis not basically temperature dependent and performs well using cold andwarm water rinse solutions. Also, the process can be conducted usingwater of any reasonable degree of hardness although, obviously, the useof softer rinse water is preferred.

Since the composition of the present invention in use tends to acidifythe rinse water, a number of additional beneficial results have beennoted, namely permanent press resins tend to be more stable ans calciumprecipitants such as CaCO tend to be removed leaving the fabrics with abetter hand and feel.

The composition of the present invention will now be more .fullyillustrated by way of the following specific examples which are for thepurpose of illustration only and are in no way to be considered aslimitive of the composition of the present invention. In the followingexamples, all parts and percentages are by weight and all temperature indegrees farenheit.

Example 1 and Comparative Examples 1 and 2 Three series ofidentical'SO/SO polyester cotton permanent press swatches are soiledwith a clay soil. These soiled swatches are then'washed with a detergentas a 1.5 g/liter concentration using a water having a hardness of 150ppm. The detergent composition is tridecylbenzene sulfonate, 2% Cetoxylated 1 1E0) alcohol, 1% sodium soap, 33% sodium carbonate, and

Example 3: andCornparative Example 4 Two sets of cotton'terry towelswatches are rinsed 7% sodium silicate. These series or sets of swatchesare 10 three times utilizing the rinse solutions as shown in then rinsedwith the following rinse composition as set Table II- forth in Table I.The swatches are then soiled, washed TABLE H and rinsed in this mannerfour additional times. The reflectance (Rd values) after the first andfifth wash are Example No Rinse Rd Value "b" shown below with a higherRd value indicating mvalue creased whiteness.

Comp. Ex. 4 0.01% solution of 74.9 4.0 TABLE I N-tallow propylenediamine Example 3 0.01% N-tallow pro- 82.5 2.7 Rd After Rd After pylenediamine Example No. Rinse 1st Wash 5th Wash 0.02% citric acid Comp. Ex.1 Water (150ppm) 75.5 59.7 C E 2 HC1+ wt 76.9 62.3

X PH er The above rinse solutions are conducted at a temper- Example I0.0 2% Citric 7 8 ature of approximately 120F. which corresponds to a ggZ normal warm water rinse. In Table II, the Rd value is As is evidentfrom Table l, the utilization of citric acid produces an increasedwhiteness from the first wash through the fifth wash with the whitenessbecoming more apparent after a greater number of washings. Since thecitric acid and hydrochloric acid rinses both have the same pH, thisshows that the increased whiteness obtained is not a function merely ofpH but can be obtained only utilizing an organic complexing acid, suchas citric acid. In each of the above noted rinse solutions, the waterwhich is utilized has a hardness of 150 ppm.

Example 2 Utilizing the procedure of Example 1, the citric acid rinse isreplaced by the following organic complexing acid rinse solutions: (A)0.01% tartaric acid; (B) 0.05% maleic acid; (C) 0.1% fumaric acid; (D)0.02% adipic acid; (E) 0.06% of a 50/50 mixture of maleic acid andcitric acid; and (F) 0.08% citric acid.

When compared to a similar swatch of fabric rinsed only in plain waterof a similar hardness, the swatches rinsed in the above acid solutionsshow increased whiteness. This increased whiteness is evident from thefirst wash and the whiteness differential increases with everysubsequent wash.

Comparative Example 3 In order to show the inoperability of the alkalimetal salts of the organic complexing acids utilized in the compositionof the present invention, the procedure of Example 1 is repeated withthe exception that the following salt solutions are utilized as therinse solution: '(A) 0.01% of the sodium salt of tartaric acid; (B)0.05% of the potassium salt of maleic acid; (C) 0.1% of the ammoniumsalt of fumaric acid; (D) 0.02% of the sodium salt of adipic acid; (E)0.06% of the sodium salts of a 50/50 mixture of maleic acid and citricacid; and (F) 0.08% of the sodium salt of citric acid.

When the swatches rinsed in each of the above solutions are comparedboth with similar swatches using a the whiteness with higher valuesindicating increased whiteness and the 12 values indicate yellownesswith higher values indicating increased yellowness. As is immediatelyapparent, the terry towel swatches which are rinsed in the diaminecitric acid show improved results over those rinsed in just the diaminealone. Furthermore, the softening of each set of swatches isapproximately equal.

Example 4 and Comparative Example 5 The procedure of Example 3 and Comp.Example 4 is repeated with the exception that the rinse solutions aremaintained at a temperature of F, i.e. a cold water rinse. The resultsare shown in Table 111.

TABLE 111 Example No. Rinse Rd Value b"Va1ue Comp. Ex. 5 0.01% solutionof 75.6 4.4

N-tallow propylene diamine Example 4 0.01% N-ta11ow 81.3 3.5

propylene diamine 0.02% citric acid Again, the diamine citric acidproduces superior results when compared to the diamine alone. Thisindicates that the temperature of the rinse water has little, if any,effect on the decreased yellowness and increased whiteness of thecomposition of the present invention.

Example 5 0.2% primary tallow amine and O. 1% of a 50/50 mixture ofcitric acid and adipic acid.

Each of the above compositions when compared to a rinse compositionutilizing only the cationic softening agent has increased whiteness anddecreased yellowness with no apparent differentiation in degree of softemng.

As is apparent by way of the foregoing examples which are for thepurposes ofillustration only, the composition and process of the presentinvention provide a rinse cycle treatment composition and process whichreduces the yellowing caused by cationic softening agents and increaseswhiteness.

What is claimed is:

l. A process for treating fabrics which are subject to yellowing inrinse water comprising laundering said fabrics and treating said fabricsat a temperature of about 70F to about 120F with an aqueous solutioncontaining from about 0.01 to about 0.1% by weight of -a complexing acidand from O to 0.1% by weight of a cationic fabric softener, wherebyyellowing imparted to said fabrics in part by said cationic fabricsoftener is substantially reduced by said complexing acid.

2. The process of claim 1 wherein the ratio of said complexing acid tosaid cationic softening agent is from 1:1 to 5:1.

3. The process of claim 1 wherein the ratio is approximatcly 2:1.

4. The process of claim 1 wherein said organic complexing acid isselected from the group consisting of citric acid, maleic acid, tartaricacid, fumaric acid, adipic acid, succinic acid and mixtures thereof.

5. The process of claim 1 wherein said acid is citric acid.

6. The process of claim 1 wherein said cationic fabric softening agentis N-tallow propylene diamine.

7. The process of claim 1 wherein said softener is included in an amountof about 0.01 to about 0.03% by weight.

8. The process of claim 1 wherein said softener is selected from thegroup consisting of cationic nitrogen containing compounds containing 1to 2 straight chained organic radicals of at least 8 carbon atoms and atleast one chain containing about 12 to about 22 carbon atoms.

9. The process of claim 8 where said softener is a quaternary ammoniumcompound of the formula wherein R is an aliphatic radical having about 8to about 22 carbon atoms, R is an aliphatic radical having about 8 toabout 22 carbon atoms or an alkyl radical having about 1 to about 4carbon atoms, R; and R are lower alkyl radicals, n is a number betweenabout 1 and about 15 and X is a water soluble salt forming anion.

1. A PROCESS FOR TREATING FABRICS WHICH ARE SUBJECT TO YELLOWING INRINSE WATER COMPRISING LAUNDERING SAID FABRICS AND TREATING SAID FABRICSAT A TEMPERATURE O ABOUT 70*F TO ABOUT 120*F WITH AN AQUEOUS SOLUTIONCONTAINING FROM ABOUT 0.01 TO ABOUT 0.1% BY WEIGHT OF A COMPLEXING ACIDAND FROM O TO 0.1% BY WEIGHT OF A CATIONIC FABRIC SOFTENER, WHEREBYYELLOWING IMPARTED TO SAID FABRICS IN PART BY SAID CATONIC TATERICSOFTENER IS SUBSTANTIALLY REDUCED BY SAID COMPLEXING ACID.
 2. Theprocess of claim 1 wherein the ratio of said complexing acid to saidcationic softening agent is from 1:1 to 5:1.
 3. The process of claim 1wherein the ratio is approximately 2:
 4. The process of claim 1 whereinsaid organic complexing acid is selected from the group consisting ofcitric acid, maleic acid, tartaric acid, fumaric acid, adipic acid,succinic acid and mixtures thereof.
 5. The process of claim 1 whereinsaid acid is citric acid.
 6. The process of claim 1 wherein saidcationic fabric softening agent is N-tallow propylene diamine.
 7. Theprocess of claim 1 wherein said softener is included in an amount ofabout 0.01 to about 0.03% by weight.
 8. The process of claim 1 whereinsaid softener is selected from the group consisting of cationic nitrogencontaining compounds containing 1 to 2 straight chained organic radicalsof at least 8 carbon atoms and at least one chain containing about 12 toabout 22 carbon atoms.
 9. The process of claim 8 where said softener isa quaternary ammonium compound of the formula